Rockwell Automation 1746-NR4 SLC RTD/Resistance Input Module User Manual - Manual (Page 138)

Publication 1746-UM008B-EN-P - December 2006
138 Glossary
remote configuration
A control system where the chassis can be located several thousand
feet from the processor chassis. Chassis communication is via the
1747-SN Scanner and 1747-ASB Remote I/O Adapter.
resolution
The smallest detectable change in a measurement, typically expressed
in engineering units (for example, 0.1 °C) or as a number of bits. For
example, a 12-bit system has 4,096 possible output states. It can,
therefore, measure 1 part in 4096.
RTD (Resistance Temperature Detector)
A temperature sensing element with 2, 3, or 4 lead wires. It uses the
basic characteristic that electrical resistance of metals increases with
temperature. When a small current is applied to the RTD, it creates a
voltage that varies with temperature. This voltage is processed and
converted by the RTD module into a temperature value.
sampling time
The time required by the A/D converter to sample an input channel.
status word
Contains status information about the channel’s current configuration
and operational state. You can use this information in your ladder
program to determine whether the channel data word is valid.
step response time
This is the time required for the A/D input signal to reach 100% of its
expected final value, given a large step change in the input signal.
update time
The time required for the module to sample and convert the input
signals of all enabled input channels and make the resulting data
values available to the SLC processor.